The umbilical cord is the conduit connecting the mother to her baby in the womb. It supplies blood, nutrients, and oxygen. However, it can sometimes make your baby’s movement through the birthing canal difficult. One such instance is a nuchal cord, when the cord gets wrapped around the baby’s neck, preventing the baby from moving during delivery. Nuchal cord is common in pregnancies and harmless in most of them.
This MomJunction post gives you details on the nuchal cord, its effect on the baby, diagnosis, and management during pregnancy or labor.
What Is A Nuchal Cord?
Nuchal cord occurs when the umbilical cord wraps 360° around the fetal neck (1). It could be a single loop or multiple loops that can be loosely or tightly wrapped around the neck.
The nuchal cord is classified into:
- Type A: Nuchal cord with a sliding pattern that can undo itself.
- Type B: Nuchal cord with a locked pattern, making a true knot that cannot be undone without assistance.
Nuchal cords are common and are routinely checked for by the doctors during delivery.
How Common Is A Nuchal Cord?
Nuchal cord occurs in 10-29% of pregnancies. Its incidence increases as the pregnancy progresses – the incidence rate is around 12% at 24 to 26 weeks and increases to 37% at term (2) (3). As mentioned earlier, the nuchal cord is a common occurrence and not a cause of worry in most cases.
The next section lists out the various reasons for the occurrence of a nuchal cord. Keep reading.
What Causes A Nuchal Cord?
Regular movement of the baby in the womb is considered to be healthy. However, a rapid fetal movement could cause a nuchal cord. Other factors that could lead to a nuchal cord include (4):
- Extra long umbilical cord
- Excess amniotic fluid that allows more fetal movement
- Single amniotic sac shared by multiples (5)
- Fetus in breech presentation (6)
- Large infant size (7)
Sometimes, nuchal cords can get wrapped tightly around the fetal neck and need to be manually untangled at the earliest to prevent any complications.
Is It Possible To Detect A Nuchal Cord?
There are no noticeable symptoms in the case of a nuchal cord as it may not affect your body in any way. So, you may not know about it until any complication arises. But should you feel a sudden slowdown in the fetal movement, tell your doctor about it and get an ultrasound done to rule out any possibilities of cord entanglement.
Your doctor may also suggest other diagnostic procedures.
How is nuchal cord diagnosed?
A nuchal cord can be assessed through the following ways (3):
- A combination of ultrasonography and color Doppler imaging can help identify 72% of single and 94% of multiple nuchal cords.
- Also, the doctor may perform a transabdominal manual compression of the fetal neck to detect the nuchal cords before delivery. During the procedure, if the fetal heart rate drops, then the test ascertains the presence of nuchal cord.
- Vibroacoustic stimulation is a non-invasive method used to detect a nuchal cord. It helps to identify the fetal heart rate deceleration, if any, at a particular frequency.
The section below tells you about the management of nuchal cord during labor.
How Is The Nuchal Cord Issue Addressed During Labor?
It is difficult to ascertain if the baby has a nuchal cord during labor. However, the doctors check for the same when the baby’s head comes out first. If the loop is loosely held around the neck, it will easily slip over the head. If not, the doctors clamp and cut the cord before the baby’s shoulder is delivered.
Instead of cutting the cord, doctors might also do a somersault maneuver (rolling feet over the head). This procedure involves somersaulting the baby’s head toward the mother’s thigh, while it emerges through the birthing canal and unwinding the cord immediately (8).
Most of the times, the nuchal cord gets unwinded on its own before delivery. Its complications are very rare. However, early detection and timely management can make the process of delivery smooth without posing any risks to the baby.
Frequently Asked Questions
1. When is a nuchal cord dangerous?
A tight nuchal cord could decrease the blood flow during the contractions, causing a drop in the fetal heart rate. If the blood flow is completely cut off before delivery, due to the compression of the cords, it could result in stillbirth (4).
2. What are the risks of nuchal cord?
Although rare, the following risks could arise when the nuchal cord gets tightened around the fetal neck (9):
- Fetal distress: Obstruction of blood flow in the thin-walled umbilical vein causing hypovolemia (decreased blood volume), acidosis, and anemia (3). This causes a deceleration in heart rate.
- Labor induction: A persistent nuchal cord along with poor fetal growth needs delivery without delay.
- Meconium staining: Distress can cause the fetus to pass meconium stool into the amniotic fluid (10).
- Five-minute Apgar score is less than 7: A test that measures the newborn’s health based on the heart rate, breathing, muscle tone, reflex response, and color (11). Ideally, the five-minute Apgar scores should be between 8 and 10, and babies scoring less could not be breathing deeply and need oxygen supply.
- Emergency c-section
3. What are the effects of a nuchal cord on the baby?
A tightly wrapped nuchal cord is associated with some physical features in the newborn. They include (3):
- Duskiness of the face, a discoloration of the facial skin can be observed.
- Facial petechiae or visible red spots on the face.
- Conjunctival hemorrhage, which is bleeding in the conjunctiva (a clear membrane that covers the white part of the eyes and lining of the eyelids)
- Facial suffusion or slow spread of the color
- Skin abrasion of the neck due to a tightly winded cord.
- Transient feeding difficulties (2)
- Hypovolemia (decreased blood volume) and hypotension resulting in acidosis (acid build-up in the blood resulting from poor lung function that drops the blood pH)
- Mild respiratory distress
These abnormalities can also raise the possibility of transient encephalopathy (a term used for brain damage, disease, or malfunction) that could lead to long term complications in the baby’s health.
The idea of nuchal cords can make any parent-to-be anxious. But note that there isn’t anything you can do to prevent it. So focus on staying healthy and keeping track of your progress, while checking in with your doctor once in a while.
Do you have any experiences to share? Share them with us in the comment section below.
2.Morarji Peesay; Cord around the neck syndrome; NCBI (2012)
3.Morarji Peesay; Nuchal cord and its implications; NCBI (2017)
4.What happens if the umbilical cord is around my baby’s neck?; The University of Texas Southwestern Medical Center
5.Preety Aggarwal, et al.; Cord entanglement in monochorionic monoamniotic twins: a case report; International Journal of Reproduction, Contraception, Obstetrics and Gynecology
6.Ultrasound determination of nuchal cord in breech presentation; American Journal of Obstetrics & Gynecology
7.Umbilical Cord Problems; Birth Injury Guide
8.Larry Reynolds; Practice Tips: ‘Somersault’ Maneuver For A Tight Umbilical Cord; Canadian Family PhysicianRhoades DA;
9. Risk factors and outcomes associated with nuchal cord. A population-based study; NCBI (1999)
10. Meconium Aspiration; Stanford Children’s Health
11.Apgar Scores; American Academy of Pediatrics